div.overflow_1 {
    width: 300px;
    height: 100px;
    border: 1px solid #ccaabb;
    overflow: hidden;
}

div.overflow_2 {
    width: 100px;
    height: 100px;
    border: 1px dashed #abcdef;
    font-size: 250%;
    overflow: auto;
}

.box {
    width: 400px;
    height: 50px;
    border: 3px solid #00ff00;
    margin-top: 10px;
    background-color: #cecece;
}

.position_static {
    position: static;
    background-color: bisque;
}

.position_relative {
    background-color: blueviolet;
    position: relative;
    /* left: 10px; */
    /* right: 50px; */
    right: -50px;     /* right: -50px;相当于left: 50px; */
    top: 20px;
    /* z-index: -100; */
    z-index: 100;
}

.position_fixed {
    background-color: royalblue;
    position: fixed;
    top: 0;
    right: 0;
}

.position_absolute {
    background-color: goldenrod;
    position: absolute;
    top: 100px;
    left: 200px;
}

.menu:hover + .absolute_menu {
    display: block;
}

.absolute_menu {
    display: none;
    background-color: hotpink;
    position: absolute;
    top: 56px;
    left: 0px;
}

.position_sticky {
    position: sticky;
    /* 为了能支持更多的浏览器，需设置position: -webkit-sticky; */
    position: -webkit-sticky;
    background-color: #667788;
    bottom: 30px;
    margin-left: 400px;
}

.box_float {
    float: left;
    background-color: red;
    margin-left: 20px;
}

.clear_float {
    clear: both;
}

li {
    float: left;
    width: 100px;
    border: 1px solid #000;
}